How are prototype functions different than normal functions in javascript ?

Question

Javascript functions can be declared on a objects prototype like this:

<object name>.prototype.<variable name>=function(){
//
//
}

How it this different than following declaration?

<object name>.<variable name>=function(){
//
//
}

How are prototype functions different than normal functions in javascript ?

Answer 1

Prototype functions are instance functions, whilst normal functions are "static" functions. Functions declared on class's prototype will available on all instances of that class.

var MyClass = function(){
};
MyClass.staticFunction = function(){alert("static");};
MyClass.prototype.protoFunction = function(){alert("instance");};

MyClass.staticFunction(); //OK
MyClass.protoFunction (); //not OK

var myInstance = new MyClass ();
myInstance.staticFunction(); //not OK
myInstance.protoFunction (); //OK